GB239873A - Improvements in or relating to frequency transformers - Google Patents

Abstract

239,873. Telefunken Ges. f³r Drahtlose Telegraphie. Sept. 12, 1924, [Convention date]. Addition to 238,559, [Class 38 (ii), Electric currents, Converting &c.]. Modulating systems and apparatus.-Relates to frequency-changing transformers in which the winding comprises a, conductor surrounded by a thin layer of ferro-magnetic material as described in the parent Specification, and consists in controlling the temperature of the transformer so as to regulate the output. The transformer may be worked at a relatively high temperature, viz., a temperature approaching the critical point of the iron, and, where sufficient heat is developed in the transformer by the high frequency currents, the transformer is merely protected from external influences by enclosing it in an evacuated container or one containing an inert gas. Fig. 1 shows such an arrangement, the winding a being supported on heat resisting rings b and enclosed in a glass, quartz, or like container c. Where insufficient heat is developed by the high frequency currents, the transformer is heated by hot gases, by electrically heated elements, or by passing low frequency or direct current directly into the transformer windings. Fig. 3 shows an arrangement in which the transformer a having high frequency leads k1, k2, brought out from the container c is supplied at equipotential points l1, l2 with a heating current controlled by means of a key. In a further arrangement, Fig. 4, the heating current is obtained from an alternating source through a rectifier g and is controlled by the exciting circuit of the rectifier the current in which is varied by the device s which may be a telephone or key for signalling purposes.